In the prior art many media have been developed for the identification of bacteria but most prior art media have had limited capabilities. Some, for example, have been used for determining only a single biochemical reaction of an unknown microorganism. Others have been compounded to identify only fermentative or non-fermentative bacteria.
A primary problem in the prior art media has been an inordinate incubation time for positive reactions. Prolonged incubation time for bacterial speciation is particularly hazardous in cases of nosocomial infections or post-operative wound infections.
Pseudomonas aeruginosa, Acinetobacter anitratus, P. maltophilia, and many other NFB are becoming increasingly recognized as important causes of infection and therefore it is mandatory that they be rapidly isolated and identified. While most commercially available isolation media are applicable for NFB, identification methodology for these organism has been inadequate.
Two known prior art media have been developed for the identification of NFB. One is disclosed in U.S. Pat. No. 3,399,115 to Sellers. This medium is capable of identifying only five species of NFB. This medium includes a large amount of organic nitrogen. In general a large amount of organic nitrogen tends to cause additional alkaline byproducts of metabolism so that positive reactions are significantly delayed and in addition unreliable results are obtained. The Sellers patent does suggest the use of inorganic nitrogen.
The second medium is disclosed in U.S. Pat. No. 4,048,016 to Otto. The Otto disclosure is essentially that of a non-growth or buffered substrate medium. For inoculation it requires a heavy inoculum, that is, an inoculum of about 10.sup.11 organisms per milliliter. This is obtained by harvesting numerous (50 to 100) bacterial colonies and requires an additional time of 24 hours for NFB identification.